Physical Layer


  • Describe the role of bits in representing a frames
Type of Physical:
  • Wireline
    • LAN (UTP, STP)
    • Cable modem coaxial
    • Fiber Optic cable (OFC)
  • Wireless
    • AP
UTP cable:
  • CAT5
  • CAT6
  • Straight through
  • Crossover
UTP pros & cons:pros:
  • Easy to use and easy to cut
  • Cheap
  • Length limit
  • Size of cable
  • Speed

Coaxial cable:
  • Coaxial cable
  • Coaxial splitter
  • Cable modem (DOCSIS 2,3)
Fiber Optic cable:รู้จักชนิดของหัว Connector และชื่อเรียกอุปกรณ์ต่างๆ
  • Single mode:
    • only 1 stream
    • far
  • Multi mode:
    • many streams/wavelength
    • short
  • LC
  • FC
  • SC

SFP Type and Length:
  • Single mode SFP
  • Multi mode SFP
  • Single mode SFP+
  • XFP 10G
  • CFP 100G
Checker equipment:
  • Power meter
  • Red Source / Red Light / Light Source
  • Traffic Checker
OFC Pros and Cons:pros:
  • High Speed
  • Long Length Limit
  • Small size cable (easy to wiring)
  • Expensive
  • Difficult to cut
  • Cracked make signal loss
  • Router - ODF - DWDM - ODF - Router
  • Long Length more than 80km
Dark Fiber:
  • Router - (ODF - ODF) - Router
  • Length depend on SFP
Optical Distribution Frames (ODF):
  • Easy to manage cables
  • ODF Box 144 core may standard in Telco
  • ODF core label
Wiring Guide:
  • Wire way fiber optic
  • Wire way fiber optic and UTP
  • Wire way under raise floor
Wiring step:
  1. choose fiber length appropriately.
  2. mark fiber optic both side with pen or sticker.
  3. wiring fiber optic on wire way (upper or under).
  4. make real label both side of cable.
  5. check over cable after wiring. (cable tie)
  6. check all of fiber optics with power meter.
  7. call site controller to cross check again.
  • Power Type (AC DC)
  • Power consumption
  • Heat
  • Breaker size:
    • Main breaker
    • Sub breaker
  • Power cable:
    • cross section area (Sqm)
    • color of cable
  • AC power strip
Wireless standard:


How to know cable length and cable type before wiring?
  • Site survey
  • Ask site controller
  • If urgent, should prepare many as you can
How to check quality of fiber optic or UTP cable?Fiber optic:
  • Use power meter.
  • Check ping on router. No loss found.
  • Check CRC error on router.
  • Loop check, ensure SFP is usable.
  • Cut hop test, ensure connector isn't broken.
How to expansion WAN link step by step?
  • Request DWDM from transmission team.
  • Wiring fiber optic.
  • Check power (dBm).
  • Ensure no routing configuration of IPs will configure
  • Configure IP WAN to ping test. (ensure IPs don't duplicate on the existing network).
  • Check CRC error.
  • Configure routing and other configuration.
  • Monitor after expansion.
How to find cable on ODF when change or remove cable?
  • Verify label on cable first. Both direction must have same label detail.
  • Verify description on configuration.
  • Cross check with DWDM document.
  • Unplug cable on line card first and check status on link.
How make port status change to "UP"?
  • Power of fiber optic in between recommend parameter.
  • Negotiate
Tip and trick check DWDM:
  • After finished wiring physical to DWDM, call to DWDM team to check power on each side.
  • Inform information of DWDM link number.
Tip and Trick to check broken SFP, broken cable:
  • Loop test TX, RX on 1 SFP.
  • Use Power meter.
  • If power high, use attenuation to reduce power.
Tip and Trick to contract site controller smoothly:
  • Always use polite speech.
  • When go to site, buy some gift. Work will be easier.
  • If use telephone, use opposite gender will talk easier.
Cr: Meng@TRUE

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    • 2.4 GHz: Less channel but far
    • 5 GHz
  • License
Cr: P'Top@TRUE